This invention relates to an oil collection apparatus for an internal-combustion engine and a method of removing oil from an internal combustion engine, in particular for a motorcycle.
In the case of internal-combustion engines, it is known to design the oil-storage tank as a so-called dry-sump lubrication in a structural space separate from the crankcase. For example, U.S. Pat. No. 4,915,070 discloses integrating an oil tank in the crankcase of an internal-combustion engine. The oil-supply, often supplied by oil channels, can likewise be arranged in the crankcase, so that the entire lubricating-oil supply of the internal-combustion engine is housed in a space-saving manner in the internal-combustion engine.
In the case of dry-sump lubrication, it is necessary for the lubricating oil arriving from the consumer devices to be conveyed by way of an oil-suction pump into the oil tank, from where it is pumped once more to the consumer devices with the aid of an oil-conveying pump. For a continuous and reliable lubricating-oil supply, it is necessary for the lubricating oil to be brought rapidly back from the crankcase to the oil-storage tank.
The present invention provides an improved motorcycle engine having a crankshaft rotatable about an axis, a crankcase housing surrounding the crankshaft, a web coupled for rotation about the crankshaft along a circular pathway, and an oil channel having a longitudinal axis that is substantially tangential to an adjacent portion of the pathway. Preferably, the motorcycle engine includes two cylinders in a V-shaped configuration. In alternative embodiments of the present invention, the engine may have any number of cylinders including one, two, three, or four. Similarly, the engine may have any number of webs for balancing the rotation of the crankshaft.
In one aspect of the present invention, the crankshaft and the web fling oil and an oil/air mixture at the walls of the crankcase housing as the crankshaft and the webs rotate about their axis. The outer surface of the web rotates in a substantially circular pathway. An oil channel is preferably located substantially tangential to the circular pathway. Because the oil channel extends partially tangentially away from the crankshaft and the web, the oil channel is able to rapidly separate the oil from the oil/air mixture and rapidly evacuate the oil from the crankcase. Preferably, a substantial amount of oil is flung directly into the oil channel and is therefore removed from the crankcase by the oil channel to an oil pump.
The remaining oil is preferably flung against the housing wall which is preferably contoured to drain the oil toward the oil channel. Most preferably, the crankcase has a first and a second curved wall portion which are contoured to encircle the web as the web rotates along its circular pathway. This substantially curved configuration helps to direct the oil away from the crankshaft and into the oil channel. Oil loss is minimized because the web flings a substantial quantity of oil directly into the oil channel. The reduction in oil loss and the rapid return of the lubricating oil allows for the output of the oil pumps to be set correspondingly lower.
A balancing shaft is commonly provided in engines of this type to balance the mass forces caused by the rotation of the crankshaft and the web about the axis. The balancing shaft is preferably parallel to the crankshaft and preferably has a balancing shaft web.
In another aspect of the present invention, the balancing shaft is surrounded by curved wall portions of the crankcase, between which an oil channel extends partially tangentially with respect to the rotational axis of the balancing shaft. Oil is preferably flung from the balancing shaft and the balancing shaft web. The second oil channel preferably collects the oil that is flung from the balancing shaft and the balancing shaft web. Additionally, the oil that is not flung directly into the second oil channel drains down the walls of the crankcase housing into the second oil channel. In this way the lubricating oil can be conveyed in a deliberate manner to the intake socket of the oil-suction pump by the rotation of the balancing shaft or the balancing shaft web.
In addition to the rapid return of the lubricating oil to the oil-storage tank, foam suppression of the lubricating oil is desired before the latter returns to the oil tank. Therefore, an oil/air separator is provided, to which the two oil channels preferably lead. The oil is removed from the crankcase by the oil channels and is fed into the oil pump via the oil/air separator. In this manner the air is separated from the oil/air mix by the separator before the oil reaches the oil pump.
In still another aspect of the present invention, the oil-storage tank is advantageously integrated in the crankcase below or to one side of the partitioned-off crank space. Further advantageous embodiments and improvements of the oil collection apparatus and method of collecting oil according to the invention for an internal-combustion engine are described below.